some of your spreads went "corrupt", I think.
Something is wrong with the spread's coordinate space.
I'd try the following:
1. Export the document to IDML
2. Open the IDML and save with a new name
If the problem still persists:
1. Add some new spreads after the one that is working ok.
2. Go to the first spread, that is "corrupt" and showing its contents "infinitely" small:
3. Select all the contents by using a selection marquee with your selection tool (black arrow).
Important: Do not use the menu command Select All.
4. Copy your selected contents.
5. Go to the first spread you added and do Paste in Place.
If that is working go on with the rest of the "corrupted" spreads.
Then delete all the "corrupted" spreads and do a "Save As" to the document with a new name.